Diabetic kidney disease is a major public health issue affecting more than 200,000 U.S. individuals with end-stage renal disease, which requires chronic hemodialysis or kidney transplantation to avoid significant morbidity and mortality. Even with the best multi- faceted approach to diabetes management the progression of diabetic nephropathy is only slowed, but not stopped. To develop more effective therapies for this disease we need to have a better understanding of the disease pathogenesis. We recently found that the expression of a protein called sirtuin (SIRT1), which is known to modify and regulate the cell's transcription machinery, is reduced in a rodent model of diabetes as well as human with diabetic nephropathy. Here, we present additional data to support that reduction of SIRT1 increases the susceptibility of mice to kidney injury. We hypothesize that reduction of SIRT1 in the diabetic condition predisposes podocytes to injury. To test our hypothesis we have generated a novel mouse model that allows us to reversibly manipulate SIRT1 expression with both temporal and tissue specificity. With this model we propose to exam the functional role of SIRT1 in the kidney podocyte by studying the development of diabetic kidney disease and podocyte injury in mice with reduced SIRT1 expression. We also aim to identify the molecular mechanism through which SIRT1 reduction causes kidney injury in diabetes. Our results could provide a better understanding of the molecular mechanism of podocyte and kidney injury in diabetes and a novel target of treatment for a disease where currently available therapy is less than optimal.